Revert "Move mojo edk into mojo/edk"

mojo/edk/embedder/platform_handle_utils_posix.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "mojo/edk/embedder/platform_handle_utils.h"
-
-#include <unistd.h>
-
-#include "base/logging.h"
-
-namespace mojo {
-namespace embedder {
-
-ScopedPlatformHandle DuplicatePlatformHandle(PlatformHandle platform_handle) {
-  DCHECK(platform_handle.is_valid());
-  // Note that |dup()| returns -1 on error (which is exactly the value we use
-  // for invalid |PlatformHandle| FDs).
-  return ScopedPlatformHandle(PlatformHandle(dup(platform_handle.fd)));
-}
-
-}  // namespace embedder
-}  // namespace mojo